Hub construction for hydraulic operated variable pitch propellers



March 17, 1942. R. J. RUTHS ETAL 2,276,347 HUB CONSTRUCTION FOR HYDRAULIC OPERATED VARIABLE PITCH PROPELLERS Filed Sept. 25, 1940 2 Sheets-Sheet 1 R. J. RUTHS EIAL Filed Sept. 25, 1940 2 Sheets-Sheet 2 INVENTORS fioaser u! farms ATTORN March 17, 1942.

HUB CONSTRUCTION FOR HYDRAULIC OPERATED VARIABLE PITCH PROPELLERS Patented Mar. 17, 1942 OFFICE HUB CONSTRUCTION FOR HYDRAULIC OPERATED VARIABLE PITCH PRO- PELLERS Robert J. Ruths, Baltimore, Md., and Harry L. Dodson, United States Navy Application September 25, 1940, Serial No. 358, 31!) 3 Claims. (Cl. 170-163) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) This invention relates to hydraulic operated variable pitch propellers, and it has a particular relation to and is an improvement on the propeller covered by U. S. Letters Patent No. 2,210,009, granted to Robert J Ruths and Harry L. Dodson.

The principal object of the present invention is the provision of a propeller of the character described, in which the hydraulically operated mechanism is housed in the propeller hub, thus not only providing a very simple, compact and easily accessible construction located outboard of the vessel, but. which renders possible the elimination of the quill shaft heretofore employed to alter the pitch of the propeller blades.

With these and other objects in view, as well as other advantages that may be incident to the use of the improvements, the invention consists in the parts and combinations thereof hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as defined in the appended claims.

-"In order to make the invention more clearly understood, there are shown in the accompanying drawings means for carrying the invention into practical use, without limiting the improvements in their useful application to the particular construction, which, for the purpose of illustration, have been made the subject of illustration.

In the accompanying drawings:

Fig. 1 is a longitudinal sectional view through a propeller hub embodying the invention; and

Figs. 2, 3, 4 and 5 are transverse step sectional views taken on lines 22, 33, 4-4 and 5-5, respectively, of Fig. 1.

Referring to the drawings, and particularly to Fig. 1 thereof, a variable pitch propeller embodying the invention is shown as comprising a tubular drive shaft l0 having a collar or annular flange ll upset or otherwise provided thereon a short distance from its after end. A block I2 is fixed to the drive shaft Ill by means of a key I3 and is provided with a plurality of radially extending stub-shafts l4, preferably three in number, and preferably cast integrally therewith. Rotatably mounted on each of the stub-shafts I4 is a propeller blade I5, which may be balanced in a well known manner so as to be what is known as a stabled blade, said blade having a root portion l6 formed with an annular shoulder I! which is seated within a groove or channel I8 formed in the block l2. The blades [5 are held against displacement by means of a pair of ring members I9 and 20 formed with complementary recesses 2i and 22 embracing the root portions l6 of the blades outside of the shoulders ll thereof and which are secured together and to the flange ll of the drive shaft II) by means of longitudinally extending bolts 23, thereby tying the parts to the drive shaft as against longitudinal displacement. The blades l5 are also each formed with a collar 24 which seats within a correspondingly shaped recess formed in the ring members l9 and 20 and which cooperate with the shoulder I! in reinforcing the blade and imparting lateral and longitudinal stability thereto. A packing ring 25 is interposed between the collar 24 and the ring members 19 and 20 to prevent leakage and the infiltration of foreign substance at this point.

A cap plate 26 is secured against the forward face of the ring member 20 by means of nuts 27 which are threaded onto reduced portions 28 formed integrally with the forward ends of the bolts 23 and extending through openings in the cap plate. Ring members 29 and 30 are secured together and to the after face of the ring member I9 by nuts 3| threaded onto reduced integral portions 32 formed on the rear end of the bolts 23, and leakage between the members 29 and 30 is prevented by an interfitting ring and groove connection 33. An annular block 34 is secured to the after face of the ring member 29 by nuts 35 threaded onto reduced integral portions 36 formed on the reduced portion 32 of the bolts 23 and a hub cap 31 of streamlined contour is secured to the after face of the block 34 by screws 38. The construction thus far described, including the ring members [9 and 20, cap plate 26, ring members 29 and 3!), block 34 and hub cap 31 form a compact assembly of streamline configuration for housing the hydraulically operated pitch controlling mechanism where it is easily accessible for assembly, replacement or repair.

The ring member 30 is formed with a concentric circular chamber 39 (Fig. 2), provided with a pair of diametrically disposed fixed vanes 40 having an oil sealing contact with an annular rotatable piston 4| provided with a pair of diametrically disposed piston vanes 42 having an oil sealing contact with the circular wall of the chamber 39 at points between the fixed vanes 40. The piston 4| is keyed to the hub portion 43 of a bevel pinion 44 which is rotatably mounted on a tubular extension 45 formed on the ring member 29 and extending forwardly into a socket 46 formed in the after end of the drive shaft l0. Suitable packing rings are provided on opposite faces of the piston 4|, between the hub 43 and ring member 38, between the pinion 44 and tubular extension 46 and between the tubular extension and the drive shaft ||l.

The bevel pinion 44 meshes with segmental bevel gears 41 which are formed on a ring 48 which are mounted on the collars H of each of the blades l for rotary adjustment by means of key pins 49. Although the bevel pinion 44 meshes with each of the segmental gears 41 so as to cause the propeller blades |5 to turn in unison when the pitch thereof is altered, addi-" tional means is provided to prevent binding of the parts which may be caused by inflltratlons of sand or the like. This consists of an idle bevel gear 50 which is rotatably mounted on a reduced portion 5| of the block |2 for intermeshing engagement with segmental bevel gears 52 formed on the rings 48 opposite to the segmental gears 41. This construction is the subject of U. S. Letters Patent No. 2,208,602.

The piston 4| is rotated in the chamber 39 in a clockwise direction by means of fluid under pressure admitted into the system from a suitable source, such as that disclosed in the above referred to patent, through a pipe 53 which extends through the drive shaft ID in spaced relation thereto. The after end of this pipe is supported by a plug 54 which is threaded into the ring member 29 and communicates with the chamber 39 on one side of the piston vanes 42 ,through ports 55 formed in the plug 54, and passageways 56 and 51 formed in the plate 29. The fluid on the opposite sides of the piston vanes 42 escapes through passages 58 and 59 (Fig. 3), the former communicating with the space 60 between the pipe 53 and the drive shaft l0 and thence through the return or low pressure side of the system to the source of supply, namely the reservoir or sump shown and described in Patent No. 2,210,009 previously referred to. If it is deof teeth 63 at their forward ends for engagement between corresponding teeth 63' (Fig; 2) formed 1 on the rear end of the hub 43 of the bevel pinion 44. The clutch 6| is urged toward its locking position by a spring 64 mounted in a retaining cage or cup 65 formed on the block 34. A ringsageway 13 corresponding to the passageway 1|. This will force the piston outwardly-and retract the clutch 6| from looking engagement with the hub 43 of the bevel pinion 44. The fluid under pressure is then free to actuate the piston 4|, as hereinbefore described. As soon as the blades ii of the propeller reach the desired pitch the flow of fluid into the system is discontinued, thus permitting the fluid in the chamber 66 to leak out of the same and into the low pressure side of the system through needle valve 15 when the fluid in passageway 56 is under pressure. However, when the fluid in passageway 58 is under pressure needle valve 14 functions to relieve the fluid to passageway 56, thus permitting the clutch to reengage under the action of the spring 64. The high or driving pressure, herein mentioned, is derived from a pump which draws oil from a sump or reservoir disclosed in said patent, so as to first actuate the clutch and subsequently to actuate the motor. When the propeller blades reach the desired pitch the pump is stopped at which time the oil in the clutch cylinder will escape therefrom under the action of the spring, thus permitting the clutch to reengage and lock the blades in their adjusted position. The 011 thus escaping from the clutch cylinder flows back to the sump or reservoir. The described operations occur in rapid sequence so as to prevent any substantial reverse movement of the blades. The clutch member 6| and piston 61 are formed with bleeder ports 16 and 11 respectively, in order that the fluid, which fills the entire assembly, may pass freely through these members when they are moved.

The exact angle of the propeller blades IS in either direction is indicated by a suitably calibrated galvanometer 18 which incorporates in its construction a balanced bridge 19 of any commercial type, indicated diagrammatically in Fig. 1. One terminal 80 of the bridge 19 is grounded to the drive shaft |0 through wire 8|, brush 82 and slip ring 83, and the other terminal 84 of the bridge 19 is connected with one terminal of a resistance element 85 mounted in one of the rings 48 of one of the blades l5, through wire 86, brush 81, slip ring 88, wire 89 and sliding contact 90, the other end of the resistance element being grounded to complete the circuit, also shown diagrammatically in Fig, 1.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of the invention, and that various changes in construction, proportion and arrangement of the advantages of the invention.

shaped chamber 66 is formed in the block 34 concentric with the cage within which a correspondingly shaped piston 61 is mounted for axial sliding movement. The piston is adjustably connected with astem 68 formed on the clutch member 6| by a nut 69 which permits the throw of the piston and force exerted by the spring 64 to be regulated. The clutch member 6| is released when it is desired to alter the pitch of the propeller blades IS in either direction by fluid under pressure which is admitted into the chamber 66 either from the passageway 56, check valve 10 and passageway 1|, or from the passageway 58, check valve 12 and a pas- The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

We claim:

1. A variable pitch propeller comprising a drive shaft; a hub carried by said drive shaft; a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof; a fluid pressure operated mo-' tor located within said hub for rotating said blade; clutch means also located within said hub for locking said blade in adjusted position; a fluid pressure operated device for actuating said clutch means; conduits forming a fluid pressure system communicating with said motor and with said device for conducting fluid under pressure to and from the same to first disengage said clutch means and then to actuate said motor; and adjustable means establishing communication between said fluid pressure operated device and the low pressure side of said system for relieving the pressure in said device at a predetermined rate when said blade is rotated to the desired pitch to permit of the engagement of said clutch means.

2. A variable pitch propeller comprising a drfve shaft; a hub carried by said drive shaft; a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof; a fluid pressure operated motor located within said hub for rotating said blade; clutch means also located within said hub for locking said blade in adjusted position; a fluid pressure operated device for actuating said clutch means; conduits forming a fluid pressure system communicating with said motor and with said device for conducting fluid under pressure to and from the same to flrst disengage said clutch means and then to actuate said motor; and a restricted passageway establishing communication between said fluid pressure operated device and the low pressure side of said system for relieving the pressure in said device at a retarded rate when said blade is rotated to the desired pitch to permit of the engagement of said clutch means.

3. A variable pitch propeller comprising a drive shaft; a hub carried by said drive shaft; a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof; a fluid pressure operated motor located within said hub for rotating said blade; clutch means also located within said hub for locking said blade in adjusted position; a fluid pressure operated device for operating said clutch means; conduits forming a fluid pressure system communicating with said motor and with said device for conducting. fluid under pressure to and from the same to first disengage said clutch means and then to actuate said motor; and a metered valve establishing communication between said fluid pressure operated device and the low pressure side of said system for relieving the pressure in said device at a predetermined rate when said blade is rotated to the desired pitch to permit of the engagement of said clutch means.

ROBERT J. RU'IHS. HARRY L. DODSON. 

